Pollinator Communities and their Ecosystem Services at Conservation Grasslands and Adjacent Croplands

Authors

Araceli Gomez Villegas, University of Nebraska-LincolnFollow

First Advisor

Julie A. Peterson

Second Advisor

Autumn Smart

Date of this Version

3-2024

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Entomology

Under the supervision of Professors Julie A. Peterson and Autumn Smart

Lincoln, Nebraska, May 2024

Comments

Copyright 2024, Araceli Gomez Villegas. Used by permission

Abstract

Pollinators are intrinsically linked to the success of unmanaged and managed ecosystems by providing pollination services that aid in the reproduction of wildflowers and many crops. Land use change, habitat loss, fragmentation, and related landscape-level phenomena (for example, increased pesticide exposure) threaten pollinators and have been associated with population declines. In the Midwestern region of the United States, land conversion of native prairies and grasslands to row-crop agriculture has been one of the largest contributors to pollinator habitat loss. Conservation programs, such as the Conservation Reserve Program, have worked towards removing environmentally sensitive lands from agriculture production and enrolling them in conservation-oriented programs and practices. The incorporation of perennial grasslands into agriculturally dominated landscapes can provide resources that support wild bees and other pollinators while also benefiting adjacent crop fields through pollination services.

This thesis examines how land use across a crop-grassland interface (crop center, crop edge, grassland edge, and grassland center) impacts wild bee abundance, species richness, and plant-bee interactions. We also examine the benefits wild bees provide unmanaged and managed ecosystems by measuring pollination services using sentinel crop (Helianthus annuus var. Sunspot) and wildflower (Phacelia tanacetifolia) plants as targets for pollinator visitation. We collected bee species from five families and found bee abundance were higher in grasslands compared to croplands. We generated an inventory of wild bees for west central Nebraska which resulted in a new state record for Protandrena abdominalis abdominalis Cresson. We found some evidence of pollinator spillover to sentinel wildflowers located within the croplands but no evidence of spillover to sentinel crop plants. These results indicate conservation grasslands do provide resources to wild bees, but conservation grassland habitats not tailored for pollinators contained sparse flowering resources. These data further document the distribution of wild bees in the state and provide insights into the ecosystem services they provide. This information can be used to better advocate for the conservation of wild bees and their habitats.

Advisors: Araceli Gomez Villegas